建造者模式

1. 建造者模式(Builder Pattern) 也叫生成器模式，其定義以下： Separate the construction of a complex object from its representation so that the same construction process can create different representations.(將一個複雜對象的構建與他的表示分離，是得一樣的構建過程能夠建立不一樣的表示。) 在建造者模式中，有以下4個角色：

• Product產品類 一般是實現了模板方法模式，也就是有模板方法和基本方法。
• Builder抽象建造者 規範產品的組件，通常是由子類實現。例子中的CarBuilder就屬於抽象建造者。
• ConcreteBuilder具體建造者 實現抽象類定義的全部方法，而且返回一個組建好的對象。
• Director導演類 負責安排已有模塊的順序，而後告訴Builder開始建造，在上面的例子中就是咱們的老大，xx公司找到老大，說我要這個或那個類型的車輛模型，而後老大就把命令傳遞給我，我和個人團隊就開始拼命的建造，因而一個項目建設完畢了。 建造者模式的通用源碼也比較簡單，先看Product類，一般它是一個組合或繼承（如模板方法模式）產生的類

package com.wzl.fea;

import java.util.ArrayList;

abstract class CarBuilder {
    public abstract void setSequence(ArrayList<String> sequence);
    public abstract CarModel getCarModel();
}

abstract class CarModel {
    private ArrayList<String> sequence = new ArrayList<String>();
    protected abstract void start();
    protected abstract void stop();
    protected abstract void alarm();
    protected abstract void engineBoom();

    final public void run() {
        for (int i = 0; i < this.sequence.size(); ++i) {
            String actionName = this.sequence.get(i);
            if (actionName.equalsIgnoreCase("start")) {
                this.start();
            }
            else if (actionName.equalsIgnoreCase("stop")) {
                this.stop();
            }
            else if (actionName.equalsIgnoreCase("alarm")) {
                this.alarm();
            }
            else if (actionName.equalsIgnoreCase("engine boom")) {
//若是是engine boom關鍵字
                this.engineBoom();
            }
        }
    }

    final public void setSequence(ArrayList sequence){
        this.sequence = sequence;
    }
}

class BenzModel extends CarModel {
    protected void alarm() {
        System.out.println("奔馳車的喇叭聲音是這個樣子的...");
    }
    protected void engineBoom() {
        System.out.println("奔馳車的引擎是這個聲音的...");
    }
    protected void start() {
        System.out.println("奔馳車跑起來是這個樣子的...");
    }
    protected void stop() {
        System.out.println("奔馳車應該這樣停車...");
    }
}

class BMWModel extends CarModel {
    protected void alarm() {
        System.out.println("寶馬車的喇叭聲音是這個樣子的...");
    }
    protected void engineBoom() {
        System.out.println("寶馬車的引擎是這個聲音的...");
    }
    protected void start() {
        System.out.println("寶馬車跑起來是這個樣子的...");
    }
    protected void stop() {
        System.out.println("寶馬車應該這樣停車...");
    }
}

class BenzBuilder extends CarBuilder {
    private BenzModel benz = new BenzModel();

    @Override
    public CarModel getCarModel() {
        return this.benz;
    }

    @Override
    public void setSequence(ArrayList<String> sequence) {
        this.benz.setSequence(sequence);
    }
}

class BMWBuilder extends CarBuilder {
    private BMWModel bmw = new BMWModel();

    @Override
    public CarModel getCarModel() {
        return this.bmw;
    }

    @Override
    public void setSequence(ArrayList<String> sequence) {
        this.bmw.setSequence(sequence);
    }
}

class CarDirector {
    private ArrayList<String> sequence = new ArrayList<>();
    private BenzBuilder benzBuilder = new BenzBuilder();
    private BMWBuilder bmwBuilder = new BMWBuilder();

    public BenzModel getABenzModel(){
        this.sequence.clear();
        this.sequence.add("start");
        this.sequence.add("stop");
        this.benzBuilder.setSequence(this.sequence);
        return (BenzModel)this.benzBuilder.getCarModel();
    }

    public BenzModel getBBenzModel(){
        this.sequence.clear();
        this.sequence.add("engine boom");
        this.sequence.add("start");
        this.sequence.add("stop");
        this.benzBuilder.setSequence(this.sequence);
        return (BenzModel)this.benzBuilder.getCarModel();
    }

    public BMWModel getCBMWModel(){
        this.sequence.clear();
        this.sequence.add("alarm");
        this.sequence.add("start");
        this.sequence.add("stop");
        this.bmwBuilder.setSequence(this.sequence);
        return (BMWModel)this.bmwBuilder.getCarModel();
    }

    public BMWModel getDBMWModel(){
        this.sequence.clear();
        this.sequence.add("start");
        this.bmwBuilder.setSequence(this.sequence);
        return (BMWModel)this.benzBuilder.getCarModel();
    }
}


public class EpCarBuilder {
    public static void main(String[] args) {
        ArrayList<String> sequence = new ArrayList<String>();
        sequence.add("engine boom");
        sequence.add("start");
        sequence.add("stop");

        BenzBuilder benzBuilder = new BenzBuilder();
        benzBuilder.setSequence(sequence);
        BenzModel benz = (BenzModel)benzBuilder.getCarModel();
        benz.run();

        CarDirector director = new CarDirector();
        //1萬輛A類型的奔馳車
        for(int i=0;i<2;i++){
            director.getABenzModel().run();
        }
        //100萬輛B類型的奔馳車
        for(int i=0;i<3;i++){
            director.getBBenzModel().run();
        }
        //1000萬輛C類型的寶馬車
        for(int i=0;i<5;i++){
            director.getCBMWModel().run();
        }


    }
}